This invention relates to a method and a system for controlling on automotive gearbox of an automotive vehicle. This invention also relates to an automotive vehicle equipped with such a system.
In the field of automotive vehicles, it is known to take into account the behaviour of a driver in order to provide him or her with more or less freedom to operate a vehicle. For instance, FR-A-2 849 251 discloses a device which progressively reduces the speed of a vehicle, in case the behaviour of the driver is not satisfactory. WO-A-2008/078088 suggests modifying a function of at least one system of a vehicle, depending on whether or not this vehicle runs under the speed limit applicable to one road. U.S. Pat. No. 5,954,617 follows a similar approach where the engine performance of a vehicle is influenced by the driver's behaviour. In particular, RPM limits of an automatic gearbox can be progressively shifted or modified in case of undesirable driver performance. These approaches reduce the functionality of a vehicle in case of driver misbehaviour, which might be problematic in some occurrences when the disabled function would be necessary, for example for a truck whose speed cannot be reduced below a preset value.
On the other hand, automated gearboxes are known and sometimes mounted on vehicles like trucks. Some of these gearboxes can work in a first full automatic mode, where the gears are automatically controlled according to preset rules. These gearboxes can also sometimes work in one or several driver initiated mode(s) where, in most cases, a higher power output can be obtained from the engine of the vehicle. Such specific modes can be used in special conditions, in particular when a high torque is needed to overtake another vehicle or when the vehicle runs on an uneven surface, such as on a construction site.
It is desirable to provide a new and alternative method for efficiently controlling an automated gearbox of an automotive vehicle, which takes into account the driver's behaviour.
To this end, an aspect of the invention concerns a control method for an automated gearbox of an automotive vehicle, this gearbox being adapted to work in a first automatic mode and in at least one second driver initiated mode, which is different from the first mode. According to an aspect of the invention, this method includes at least a first step a) where the vehicle driving behaviour is monitored, a second step b) where the vehicle driving behaviour is analyzed and determined to be satisfactory or non satisfactory and a third step c) where, when the driver requests switch of the automatic gearbox from the first mode to the second mode, the switch order is followed only if, in step b), the vehicle driving behaviour is determined to be satisfactory; and/or when the automated gearbox is in a second driver initiated mode, causing a switch of the gearbox to a first automatic mode if, in step b), the vehicle driving behaviour is determined to be non-satisfactory (B=NOK).
Thanks to an aspect of the invention, it is possible to modify the global response of a vehicle to the driver's requests, without acting on the engine itself or the maximum speed of the vehicle, thanks to the control of the switch of the automated gearbox, from its first automatic mode, which is a default mode, to one of the second driver initiated modes and/or by forcibly causing the gearbox to be switched back from the second mode to the first mode. Of course, it is possible to provide that such access limitation steps may be ignored by the system or may be overruled by the driver, for example for safety concerns.
According to further aspects of the invention which are advantageous but not compulsory, such a method may incorporate one or several of the following features:                In step a), monitoring of the vehicle driving behaviour is made on the basis of at least one parameter representative of at least one of the following quantities; instantaneous and/or average fuel consumption, engine speed and/or torque, accelerator pedal and/or brake pedal and/or steering wheel movements speed and/or amplitude, brake torque and/or brake phases, intervention of ABS and/or ESP and/or ASR systems, vehicle yaw rate, vehicle speed as compared to a speed limit, distance to a preceding vehicle.        In step a), monitoring of the vehicle driving behaviour can be made on the basis of data collected on the observance of traffic rules.        The second driver initiated mode can be selected amongst the following modes: accelerator pedal kick down mode, manual mode, temporary manual mode, power/construction mode.        Steps a) and b) can be implemented continuously during a vehicle journey or step b) can be automatically implemented when a request is received to switch the automated gearbox from its first mode to its second mode.        If switch of the automatic gearbox is requested and the vehicle driving behaviour is determined to be non satisfactory, a warning message can be sent to the driver.        As long as the vehicle driving behaviour is determined to be non-satisfactory in step b), blocking of any switch order occurs and, if the vehicle driving behaviour is later determined to be satisfactory, a switch order can be followed, as long as the vehicle driving behaviour is determined to be satisfactory.        When the vehicle driving behaviour is determined to be non-satisfactory in step b), blocking of any switch order may occur for at least a given period of time or for a given distance.        
The invention also concerns a system which enables implementation of the here-above mentioned method. Such a system is for controlling an automated gearbox of an automotive vehicle, this gearbox being adapted to work in a first automatic mode and at least one second driver initiated mode which is different from the first mode. According to the invention, this system includes first means to automatically monitor the vehicle driving behaviour, second means to automatically assess whether or not this behaviour is satisfactory and third means to automatically and selectively block an order to switch the automated gearbox from its first mode to its second mode and/or to automatically and selectively switch back the gearbox from the second mode to the first mode, on the basis of an output of the second means.
According to further advantageous but not compulsory aspects of the invention, such a system can incorporate one or several of the following features:                The automatic gearbox can be an automated manual transmission device, an automatic gearbox or a continuous variable transmission.        The first, second and third means can be included in an electric, control unit,        
Finally, the invention concerns an automotive vehicle, in particular a truck, equipped with a system for controlling its automated gearbox as mentioned here-above.